ES2581452T3 - Vitroceramic glass and lithium silicate glass with transition metal oxide - Google Patents

Abstract

Lithium silicate dental glass ceramic, which contains 54.0 to 80.0% by weight of SiO2 and 9.0 to 30.0% by weight of transition metal oxide selected from the group consisting of yttrium oxides , transition metal oxides with an atomic number between 41 and 79 and mixtures of these oxides.

Description

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DESCRIPTION

Vitroceramica and lithium silicate glass with transition metal oxide.

The present invention relates to glass ceramics and lithium silicate glasses with a high content of an element with a high atomic number, which are suitable in particular for use as dental materials, for example for the manufacture of dental restorations.

The lithium silicate hobs are characterized by very good mechanical properties, which is why they have been used for a long time in the dental sector, and in this, in particular, for the manufacture of dental crowns and small bridges. Known lithium silicate hobs usually contain as main components SiO2, U2O, AhO3, an alkali metal such as Na2O or K2O and nucleating agents such as P2O5. They may also contain as other components, for example, additional alkali metal oxides and / or alkaline earth metal and / or ZnO oxides. Also known are ceramic hobs that contain reduced amounts of additional metal oxides and in particular dye and fluorescent metal oxides

EP 1 505 041 describes lithium silicate hobs that may additionally contain 0 to 2% by weight of ZrO2, as well as 0.5 to 7.5% by weight and in particular 0.5 to 3.5 % by weight of dyeing and fluorescent metal oxides. EP 1 688 398 describes similar lithium silicate hobs that are essentially free of ZnO and in addition to dye and fluorescent metal oxides in the amounts indicated above may also contain 0 to 4% by weight of ZrO2, preferably to achieve resistance high, however, smaller amounts from 0 to 2% by weight of ZrO2. In vitroceramics are processed in particular in the form of lithium metasilicate vitroceramics by means of CAD / CAM procedures to give the desired dental restorations, producing a subsequent thermal treatment the transformation of the metasilicate phase into the high resistance disilicate phase.

US Patent 6,455,451 relates to ceramic hobs that in addition to other components may also contain transition metal oxides. In this regard, it is proposed, among other things, to increase the refractive index of the glass matrix, the addition of small amounts of heavy elements such as Sr, Y, Nb, Cs, Ba, Ta, Ce, Eu or Tb. Thus, for example, CeO2 and Tb4O7 may be used in amounts of 0 to 1% by weight, Nb2O3 and Ta2O5 in amounts of 0 to 2% by weight and ZrO2 and Y2O3 in amounts of 0 to 3% by weight. In one embodiment, Ta2O5 may be present in an amount of 0.5 to 8% by weight, the specific examples, however, being a maximum of 2.02% by weight of this oxide.

US 5,176,961 and US 5,219,799 disclose ceramic hobs, for example for the manufacture of dishes, which as colorants can contain certain transition metal oxides such as CeO2, Co3O4, Cr2O3, CuO, Fe2O3, MnO2, NiO and V2O5 in an amount of 0.01 to 7% by weight.

US 5,507,981 and US 5,702,514 describe procedures for the conformation of dental restorations as well as ceramic hobs that can be used in these procedures. In this regard, they are in particular lithium disilicate glass ceramics, which may contain from 0 to 5% by weight of coloring oxides such as SnO2, MnO, CeO, Fe2O3, Ni2O, V2O3, Cr2O3 or TiO2.

Known lithium silicate-based hobs often have optical properties that do not meet aesthetic requirements to a sufficient extent, particularly with regard to their use as dental materials. Thus, known ceramic hobs often have an inadequate refractive index. In particular, in vitroceramics there is the problem that refractive indices of the crystalline phase and the vitreous phase usually differ clearly from each other, which in most cases results in the unwanted cloudiness of the ceramic hob. Similar problems exist, for example, in the case of composite materials, since the refractive indices of known ceramic and known glass differ usually from those of the polymeric phase. There is, therefore, the need for glass ceramics and lithium silicate-based glass whose refractive index can be varied in a simple way, but without, in this regard, the rest of the properties are essentially impaired. In addition, it is desirable that such hobs can be manufactured and crystallized under conditions comparable to those of usual hobs.

This objective is achieved by means of the lithium silicate dental glass according to one of claims 1 to 11 and 14. The lithium silicate dental glass according to one of claims 12 to 14, the manufacturing process of the glass and ceramic according to claim 15, as well as its use according to claim 16.

The lithium silicate dental ceramic according to the invention is characterized in that it contains from 54.0 to 80.0% by weight of SiO2 and from 9.0 to 30.0% by weight of a transition metal oxide selected from the group consisting of yttrium oxides, transition metal oxides with an atomic number of 41 to 79 and mixtures of these oxides.

In general it is preferred that the transition metal oxide does not produce, as a component of the ceramic hob according to

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the invention or of the glass according to the invention, no color change with respect to a glass ceramic or a corresponding glass without the addition of this component. In particular, the transition metal oxide is colorless and / or non-fluorescent.

Preferably, the transition metal oxide is selected from the group consisting of oxides of Y, Nb, La, Ta, W and mixtures of these oxides.

In this regard, ceramic hobs containing 9.0 to 25.0% by weight, in particular 9.5 to 20.0% by weight, preferably 10.0 to 18.0% by weight, are more preferred. preferably from 10.5 to 16.0% by weight and most preferably from 11.0 to 15.0% by weight of transition metal oxide selected from one or more of the groups mentioned above.

Surprisingly, using the high content according to the invention of transition metal with a high atomic number, the refractive index of lithium silicate glass and glass based refraction can be adjusted in a simple manner, without essentially damaging the other properties. In particular, it has been unexpectedly demonstrated that generally the high content of transition metal with a high atomic number neither prevents the desired crystallization of lithium disilicate nor leads to the formation of unwanted secondary crystalline phases, so that the ceramic hobs according to The invention is obtained with excellent optical and mechanical properties.

In addition, a ceramic hob containing 60.0 to 70.0% by weight of SiO2 is preferred.

In addition, a ceramic hob containing 11.0 to 19.0 and in particular 12.0 to 15.0% by weight of Li2O is preferred.

It has been shown that it is particularly preferred that the ceramic hob contains from 0.5 to 12.0 and in particular from 2.5 to 6.0% by weight of nucleating agents. Preferred nucleating agents are selected from P2O5, TiO2, metals, for example Pt, Pd, Au, Ag, or mixtures thereof. Particularly preferred, the hob contains P2O5 as a nucleating agent. Surprisingly, in particular P2O5 as a nucleating agent produces the formation of desired lithium disilicate crystals and prevents, on the other hand, extensively, the formation of unwanted secondary crystalline phases.

The ceramic hob according to the invention preferably contains an additional alkali metal oxide in an amount of 0.5 to 13.0, preferably 1.0 to 7.0, and particularly preferably 2.0 to 5.0% by weight. . The term "additional alkali metal oxide" refers to an alkali metal oxide with the exception of Li2O. The additional alkali metal oxide is in particular K2O, Cs2O and / or Rb2O and K2O is particularly preferred. It is accepted that the use of K2O, unlike the Na2O used in conventional ceramic hobs, contributes to the reinforcement of the glass network. It is preferred that the hob contains less than 2.0, in particular less than 1.0, preferably less than 0.5 and particularly preferably essentially no Na2O.

It is also preferred that the ceramic hob contains up to 6.0% by weight and in particular 0.1 to 5.0% by weight of alkaline earth metal oxide, the alkaline earth metal oxide being in particular CaO, BaO, MgO, SrO or a mixture thereof.

In addition, it is preferred that the hob contains up to 6.0% by weight and in particular 0.1 to 5.0% by weight of ZnO.

The ceramic hob according to the invention may also contain additional components that are selected in particular from oxides of trivalent elements, oxides of additional tetravalent elements, oxides of additional pentavalent elements, fusion accelerators, dyes and fluorescent agents.

It is preferred that the ceramic hob contains from 0.2 to 8.0, in particular from 1.0 to 7.0 and preferably from 2.5 to 3.5% by weight of an oxide of trivalent elements, this oxide being selected, in in particular, of Al2O3, Bi2O3 and mixtures thereof, preferably Al2O3.

The term "oxides of additional tetravalent elements" designates oxides of tetravalent elements with the exception of SiO2. Examples oxides of additional tetravalent elements are ZrO2, SnO2 and GeO2 and in particular ZrO2.

The expression "oxides of additional pentavalent elements" designates oxides of pentavalent elements with the exception of P2O5. An example of an additional pentavalent element oxide is Bi2O5.

A ceramic hob containing at least one additional tetravalent oxide or an additional pentavalent oxide is preferred.

Examples of fusion accelerators are fluorides.

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Examples of dyes and fluorescent agents are dyes or fluorescent oxides of dyf elements, such as, for example, the oxides of Sc, Ti, Mn, Fe, Ag, Ce, Pr, Tb, Er and Yb, in particular Ti, Mn, Fe, Ag, Ce, Pr, Tb and Er.

In particular, a ceramic hob containing at least one and preferably all of the following components is preferred:

 Component

 % in weigh

 SiO2

 from 54.0 to 80.0, in particular from 60.0 to 70.0

 Li2O

 from 11.0 to 19.0, in particular from 12.0 to 15.0

 K2O

 from 0.5 to 13.5, in particular from 1.0 to 7.0

 Al2O3

 from 0.2 to 8.0, in particular from 1.0 to 7.0

 Alkaline earth oxide

 from 0 to 6.0, in particular from 0.1 to 5.0

 ZnO

 from 0 to 6.0, in particular from 0.1 to 5.0

 Transition metal oxide

 from 9.0 to 30.0, in particular from 9.0 to 25.0

 P2O5

 from 0.5 to 12.0, in particular from 2.5 to 6.0

 ZrO2

 from 0.1 to 4.0, in particular from 0.5 to 2.0

 Dyes and fluorescent agents

 from 0.1 to 8.0 in particular from 0.2 to 2.0.

The expression used hereinafter "main crystalline phase" designates the crystalline phase that has the highest volume ratio with respect to other crystalline phases.

The ceramic hob according to the invention preferably has lithium metasilicate as the main crystalline phase. In particular, the ceramic hob contains more than 5% by volume, preferably more than 10% by volume and more preferably more than 15% by weight of lithium metasilicate crystals, with respect to the whole of the hob.

In another particularly preferred embodiment, the ceramic hob has lithium disilicate as the main crystalline phase. In particular, the ceramic hob contains more than 5% by volume, preferably more than 10% by volume and more preferably more than 15% by weight of lithium disilicate crystals, with respect to the whole of the hob.

The lithium disilicate glass ceramic according to the invention is characterized by particularly good mechanical properties and can be obtained by thermal treatment of the lithium metasilicate glass ceramic according to the invention.

It is also surprising that the lithium disilicate glass ceramic according to the invention, despite its high oxide content of a transition metal with a high atomic number, generally has a good translucency and does not show any amorphous phase separation in it. amorphous and therefore can be used for example for an aesthetically attractive coating of dental restorations.

The lithium disilicate glass ceramic according to the invention has good mechanical properties and a high resistance to chemicals.

The invention also relates to a lithium silicate dental glass containing from 54.0 to 80.0% by weight of SiO2, from 11.0 to 19.0% by weight of Li2O and from 9.0 to 30, 0% by weight of transition metal oxide selected from the group consisting of yttrium oxides, transition metal oxides with an atomic number of 41 to 79 and mixtures of these oxides. With regard to preferred embodiments of this glass we refer to the preferred embodiments of the ceramic hobs according to the invention described above. It has been surprisingly shown that despite the high transition metal content with a high atomic number, homogeneous transparent glasses can be obtained that in no way show unwanted phenomena such as amorphous-amorphous phase separation or spontaneous crystallization. These glasses are, therefore, suitable for the manufacture of the ceramic hob according to the invention. Alternatively, its use is also possible, for example as a filler material, for example in dental materials, in particular in inorganic-organic composites. The subject of the invention is also a polymerizable composition containing a ceramic hob or glass as described above and at least one polymerizable monomer. Suitable monomers and other components of composite materials are known to the skilled person.

Particularly preferred is a lithium silicate glass with crystalline germs that are suitable for the formation of lithium metasilicate and / or lithium disilicate crystals.

The glass according to the invention with crystalline germs can be produced by thermal treatment of a starting glass with the corresponding composition. By means of another term treatment the lithium metasilicate glass ceramic can be formed after the invention, which in turn can be transformed into the lithium disilicate glass ceramic according to the invention by another thermal treatment. Consequently, the starting glass, the glass with crystalline germs and the lithium metasilicate glass ceramic can be considered precursors for the

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High strength lithium disilicate glass ceramic production.

The vitroceramics according to the invention and the glass according to the invention are present in particular in the form of powder or raw parts, since in these forms they can be further processed in a simple manner. However, they may also be present in the form of dental restorations, such as intracoronary restorations (inlays), extracoronary restorations (onlays), crowns or esthetic veneers.

The invention also relates to a manufacturing process of the ceramic hob according to the invention and of the glass with crystalline germs according to the invention, in which a starting glass with the components of the hob or glass is subjected to at least one treatment thermal in the range of 450 to 950 ° C.

The starting glass therefore contains 9.0 to 30.0% by weight of oxide of at least one transition metal as defined above. In addition, it also preferably contains adequate amounts of SiO2 and Li2O, to enable the formation of a lithium silicate hob. It may also contain the starting glass other components, such as those indicated above for the lithium silicate hob according to the invention. In this regard, the embodiments that have also been indicated for ceramic hob are preferred as preferred.

In particular, for the manufacture of the starting glass, a mixture of suitable starting materials is melted, such as, for example, carbonates, oxides, phosphates and fluorides, at temperatures of, in particular, 1,300 to 1,600 ° C, preferably 1,450 at 1,500 ° C, for 2 to 10 h. To achieve a particularly high homogeneity, the molten glass obtained is poured into water, to form a glass granulate and the granulate obtained, then melted again.

The molten material can then be poured into molds, to produce raw pieces of the starting glass, called bulk pieces of bulk glass or monolithic blanks. Preferably, the cooling is performed from a temperature of 500 ° C with a cooling rate of 3 to 5 K / min to room temperature. This is particularly advantageous for achieving glass products without stress.

It is also possible to arrange the molten material again in water to produce a granulate. This granulate can then be pressed after grinding and, if necessary, the addition of other components, such as dyes and fluorescent agents, to give a blank, called a pressed powder.

Finally, the starting glass can also be processed after a granulation to give a powder.

Next, the starting glass, for example in the form of a bulk piece of massive glass, a pressed piece of powder or in the form of powder, is subjected to at least one heat treatment in the range of 450 to 950 ° C. It is preferred that a first thermal treatment to make a glass with crystalline germs according to the invention that is suitable for the formation of lithium metasilicate crystals and / / is carried out first at a temperature in the range of 500 to 600 ° C. or glass disilicate. This glass can then be subjected, preferably, to at least one other heat treatment at a higher temperature and in particular higher than 570 ° C, to produce the crystallization of lithium metasilicate or lithium disilicate.

The at least one thermal treatment that is carried out in the process according to the invention can also be carried out within the framework of a pressing or sintering of the glass according to the invention or of the ceramic hob according to the invention on a ceramic.

From the ceramic hob according to the invention and the glass according to the invention, dental restorations such as intracoronary restorations, extracoronary restorations, crowns or esthetic veneers can be manufactured. The invention also relates, therefore, to its use for the manufacture of dental restorations.

Due to the properties set forth above of the ceramic hob according to the invention and of the glass according to the invention, as its precursors, these are suitable in particular also for use in dental medicine. Therefore, an object of the invention is also the use of the ceramic hob according to the invention or of the glass according to the invention as dental material and in particular for the manufacture of dental restorations or as a coating material for dental restorations, such as crowns and bridges

The invention will be explained in detail below by way of examples.

Examples

Example 1 to 9 - Composition and crystalline phases

A total of 9 glass and ceramic hobs were manufactured according to the invention with the composition indicated in Table 1 (in each case in% by weight) by fusion of the corresponding starting glasses and subsequent thermal treatment for controlled nucleation and crystallization.

First, the starting glasses of massive rods of 100 to 200 g were melted from the usual raw materials at 1400 to 1500 ° C and by pouring into water they were transformed into glass frits. These glass frits were melted for homogenization subsequently a second time at 1450 to 1550 ° C for 1 to 3 h. The 5 molten glasses obtained were poured into preheated molds to produce glass monoliths. These glass monoliths were then transformed by thermal treatment in glasses and glass ceramics according to the invention.

The crystalline phases obtained after finishing all the thermal treatments were determined by high temperature X-ray diffraction (HT-XRD) at the temperatures indicated in each case in Table 1. Surprisingly always obtained were ceramic hobs with lithium disilicate as phase. main crystalline Despite the high content of transition metals with a high atomic number, no secondary crystalline phase was found with these transition metals.

Finally, the refractive indices of the corresponding crystalline phases were determined by means of ABBE refractometry (20 ° C, 589 nm). In this regard, it is shown that the vitroceramics according to the invention have a refractive index clearly higher than the comparison ceramic hobs.

Table I

 OR)

 54.5 0.5 11.3 0.5 3.2 30.0

 oo

 00 CD or CM with "o o LO" o oo "o o" o LO _ o n o CJ U o in CL ° 5 5 § CD 00 LO LO

 cd "CD a> cm" 00 co "a> cm" o o o "o o" o o o o CM Yes O S3 | CM CM "3- LO

 (OR

 cd "CD a> cm" 00 co "a> cm" o o o "o o" o LO -—v o o CM O OT g □ «CO O" 3- LO

 00 CD or CM with "o o lo" O oo "o o" o O o o CM Yes O S3 | CO, ^ r CD LO

 o r * - "CD a> cm" o o o "O CO o" o "o o" o LO -—- o o CM O "3- O), ^ r LO

 CO

 LO CO CD 00 cm "CM co" lO cm "o o o o" o LO "T -—V o o o CM ~ O m £ g ■ 5 <; S CO LO LO LO

 CM

 CD "CD a> cm" 00 co "a> cm" o O o "o o" o LO ---- v o o CM O OT g □ «h-, ^ r LO LO

 with "LO or cm" or LO cm "or" CM o o "or

 CM O i /) or CM or CM Li CO or CM <id or CM Q. if) or § if) or CM nz in or CM GJ H co or CM GJ -1 CO or CM> - CM OV or CO or CM LU r'- on H rc E 3 (0 Crilstalin phase (s) HT-XRD T3 «= 8-5 ~ or T3 ns. EX = 0)

Claims (16)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 55 1. Lithium silicate dental vitroceramics, containing 54.0 to 80.0% by weight of SiO2 and 9.0 to 30.0% by weight of transition metal oxide selected from the group consisting of oxides of yttrium, transition metal oxides with an atomic number between 41 and 79 and mixtures of these oxides. 2. Vitroceramics according to claim 1, containing 9.0 to 30.0% by weight of transition metal oxide selected from the group consisting of oxides of Y, Nb, La, Ta, W and mixtures of these oxides . 3. Vitroceramics according to claim 1 or 2, containing from 9.0 to 25.0% by weight, in particular from 9.5 to 20.0% by weight, preferably from 10.0 to 18.0% by weight , more preferably from 10.5 to 16.0% by weight and more preferably from 11.0 to 15.0% by weight of transition metal oxide. 4. Vitroceramics according to one of claims 1 to 3, containing from 60.0 to 70.0% by weight of SiO2. 5. Vitroceramics according to one of claims 1 to 4, containing from 11.0 to 19.0 and in particular from 12.0 to 15.0% by weight of Li2O. 6. Vitroceramics according to one of claims 1 to 5, containing from 0.5 to 12.0 and in particular from 2.5 to 6.0% by weight of nucleating agents, the nucleating agents being selected from P2O5 , TiO2 and / or metals, preferably P2O5. 7. Vitroceramics according to one of claims 1 to 6, which also contains an additional alkali metal oxide in an amount between 0.5 and 13.5, preferably between 1.0 and 7.0 and in a form particularly preferred between 2.0 and 5.0% by weight, the additional alkali metal oxide being K2O, Cs2O and / or Rb2O and preferably K2O. 8. Vitroceramics according to one of claims 1 to 7, containing up to 6.0% by weight and in particular 0.1 to 5.0% by weight of alkaline earth metal oxide, the alkaline earth metal oxide being preferably CaO , BaO, MgO and / or SrO, and / or contain up to 6.0% by weight and in particular 0.1 to 5.0% ZnO. 9. Vitroceramics according to one of claims 1 to 8, containing from 0.2 to 8.0, in particular from 1.0 to 7.0 and preferably from 2.5 to 3.5% by weight of elements oxide trivalent, the oxide being trivalent elements, in particular A ^ O3 and / or Bi2O3 and preferably A ^ O3. 10. Vitroceramics according to one of claims 1 to 9, containing at least one additional tetravalent element oxide, in particular ZrO2, SnO2 or GeO2, or an additional pentavalent element oxide, in particular Bi2O5. 11. Vitroceramics according to one of claims 1 to 10, containing at least one and preferably all of the following components:

 Component

 % in weigh

 SiO2

 from 54.0 to 80.0, in particular from 60.0 to 70.0

 Li2O

 from 11.0 to 19.0, in particular from 13.0 to 17.0

 Al2O3

 from 0.2 to 8.0, in particular from 1.0 to 7.0

 K2O

 from 0.5 to 13.5, in particular from 1.0 to 7.0

 Alkaline earth oxide

 from 0 to 6.0, in particular from 0.1 to 5.0

 ZnO

 from 0 to 6.0, in particular from 0.1 to 5.0

 Transition metal oxide

 from 9.0 to 30.0, in particular from 9.0 to 25.0

 P2O5

 from 0.5 to 12.0, in particular from 2.5 to 6.0

 ZrO2

 from 0.1 to 4.0, in particular from 0.5 to 2.0

12. Lithium silicate dental glass, containing 54.0 to 80.0% by weight of SiO2, 11.0 to 19.0% by weight of Li2O and 9.0 to 30.0% by weight of transition metal oxide selected from the group consisting of yttrium oxides, transition metal oxides with an atomic number between 41 and 79 and mixtures of these oxides. 13. Glass according to claim 12, wherein the glass contains crystalline germs, which are suitable for the formation of crystals of lithium metasilicate and / or lithium disilicate. 14. Vitroceramics according to one of claims 1 to 11 or glass according to one of claims 12 or 13, which are present in the form of a powder, a blank or a dental restoration. 15. Process for the manufacture of vitroceramics according to one of claims 1 to 11 or 14 or of the glass according to one of claims 12 to 14, wherein a starting glass with the components of the vitroceramic or of the glass is subjected to at least one heat treatment in the range between 450 and 950 ° C. 16. Use of the ceramic hob according to one of claims 1 to 11 or 14 or of the glass according to one of claims 12 to 14 as dental material and in particular for the coating of dental restorations and 5 for the manufacture of dental restorations and as loading material in inorganic-organic composite materials.